In the Host Identity Protocol (HIP) [1] Working Group at the IETF there is a draft on Rendezvous Server (RVS) functionality [2]. An RVS is used as a fixed anchor point from which a mobile HIP node can be reached. A HIP node registered at an RVS informs the RVS of the locators via which the HIP node is reachable. This way HIP nodes that want to contact the mobile HIP node can always reach it via the RVS that has up-to-date locator information of the mobile HIP node.
To be able to utilize the RVS for locating another HIP node, the HIP node initiating the connection needs to know the locator of the RVS. The current proposal is that the IP address of the RVS is found in DNS along with the Identity of the mobile HIP node. However, this requires that information is updated at the DNS for each HIP node that wants to be registered at an RVS. This might not be feasible in all situations, e.g. in military networks or other more or less private networks that at least partly share the public network infrastructure. In these networks it might also be that DNS is not available at all or is only available sporadically.
Robustness of the RVS system is also a problem in the current solution. For example, if an RVS is suddenly removed from the network, it is not possible to contact a destination host registered at the RVS even if there is a path to that host.
The article entitled “A HIP Based Network Mobility Protocol”, Szabolcs Nováczki, Proc. of the 2007 International Symposium on Applications and the Internet Workshops (SAINTW'07), 15-19 Jan. 2007, describes a HIP extension for supporting moving networks. The proposal makes use of a hierarchical local rendezvous server (LRVS) structure to route traffic between the Internet and mobile nodes. For a given mobile node, following registration with the local network, traffic will always pass between the LRVS server to which the node is registered and the root LRVS that connects to the Internet. Within the Internet the RVS structure described above is implemented. As discussed, this RVS structure can make use of the DNS to allow HIP nodes to determine contact information for peer nodes (using a HIT lookup). The LRVS structure does not itself allow mobile nodes registered with the local network to identify contact addresses for peer nodes.